In a large mixing bowl, beat butter and brown sugar until creamy.
Add egg, egg yolk, and vanilla extract, beating until combined.
In a medium bowl, whisk together flour, cornstarch, baking soda, and salt.
Add the dry ingredients to the mixing bowl, and beat until combined.
Fold in semi-sweet chocolate chips.
Spray a 9-inch pie plate with non-stick spray.
Press dough evenly into the bottom and up the sides of the pie plate.
Bake at 350 degrees for 30-35 minutes, or until the edges and top are golden, the center appears crackly and set, and a toothpick inserted near the center comes out clean.
Crust will have puffed and risen, this is normal. It will deflate as it cools. Remove the cookie crust from the oven, and while crust is still hot, use the bottom and sides of a glass or a measuring cup to lightly reshape the crust, if needed, into a pie crust form.
Cool completely on a wire rack.
Prepare peanut butter pie filling.